﻿// Copyright (c) Argo Zhang (argo@163.com). All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
// Website: https://www.blazor.zone or https://argozhang.github.io/

using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Components;
using Microsoft.AspNetCore.Components.Authorization;
using Microsoft.AspNetCore.Components.Rendering;
using Microsoft.AspNetCore.Components.Routing;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics.CodeAnalysis;
using System.Threading.Tasks;

namespace BootstrapBlazor.Components
{
    /// <summary>
    /// 
    /// </summary>
    internal class BootstrapBlazorAuthorizeView : ComponentBase
    {
        /// <summary>
        /// 获得/设置 路由关联上下文
        /// </summary>
        [Parameter]
        [NotNull]
        public RouteContext? RouteContext { get; set; }

        /// <summary>
        /// 获得/设置 NotAuthorized 模板
        /// </summary>
        [Parameter]
        public RenderFragment? NotAuthorized { get; set; }

        /// <summary>
        /// The resource to which access is being controlled.
        /// </summary>
        [Parameter]
        public object? Resource { get; set; }

        [CascadingParameter]
        private Task<AuthenticationState>? AuthenticationState { get; set; }

        [Inject]
        private IAuthorizationPolicyProvider? AuthorizationPolicyProvider { get; set; }

        [Inject]
        private IAuthorizationService? AuthorizationService { get; set; }

#if NET6_0_OR_GREATER
        [Inject]
        [NotNull]
        private NavigationManager? NavigationManager { get; set; }
#endif

        private bool Authorized { get; set; }

        /// <summary>
        /// OnInitializedAsync 方法
        /// </summary>
        /// <returns></returns>
        protected override async Task OnInitializedAsync()
        {
            Authorized = RouteContext.Handler == null
                || await RouteContext.Handler.IsAuthorizedAsync(AuthenticationState, AuthorizationPolicyProvider, AuthorizationService, Resource);
        }

        /// <summary>
        /// BuildRenderTree 方法
        /// </summary>
        /// <param name="builder"></param>
        protected override void BuildRenderTree(RenderTreeBuilder builder)
        {
            // 判断是否开启权限
            if (Authorized && RouteContext.Handler != null)
            {
                var index = 0;
                builder.OpenComponent(index++, RouteContext.Handler);
                foreach (var kv in (RouteContext.Parameters ?? new ReadOnlyDictionary<string, object>(new Dictionary<string, object>())))
                {
                    builder.AddAttribute(index++, kv.Key, kv.Value);
                }
#if NET6_0_OR_GREATER
                BuildQueryParameters();
#endif
                builder.CloseComponent();
            }
            else
            {
                builder.AddContent(0, NotAuthorized);
            }

#if NET6_0_OR_GREATER
            void BuildQueryParameters()
            {
                var queryParameterSupplier = QueryParameterValueSupplier.ForType(RouteContext.Handler);
                if (queryParameterSupplier is not null)
                {
                    // Since this component does accept some parameters from query, we must supply values for all of them,
                    // even if the querystring in the URI is empty. So don't skip the following logic.
                    var url = NavigationManager.Uri;
                    var queryStartPos = url.IndexOf('?');
                    var query = queryStartPos < 0 ? default : url.AsMemory(queryStartPos);
                    queryParameterSupplier.RenderParametersFromQueryString(builder, query);
                }
            }
#endif
        }
    }
}
